Preterm birth (birth at less than 37 weeks gestation) is a problem of great public health significance because it is a leading factor that determines the dismal infant mortality rate in the United States. Preterm birth is a major determinant of infant mortality, and a leading contributor to infant and childhood morbidity. Prior research has identified a number of risk factors for preterm birth (e.g., single parenthood, low income), but even when one considers all of the known risks, the etiology of this problem is not fully understood. A risk of potential significance may be maternal depressive symptoms. Recent research has demonstrated that those women with higher levels of depressive symptoms have higher levels of deleterious health behaviors (e.g., cigarette smoking) that affect pregnancy outcome. One retrospective study also demonstrated an association between depressive symptoms and pregnancy outcomes. However, since the depressive symptoms were measured after the birth of the child, responses may have been biased by the outcome of the pregnancy. No prior prospective study has tested hypotheses about the association between depressive symptoms and preterm birth. In the proposed study, data will be used that were collected as part of a prospective study of psychosocial factors and low birthweight (funded by NICHD). As part of the currently funded project, a screening tool was administered to pregnancy women to measure depressive symptoms, and length of gestation was identified at the end of the pregnancy. Data about health-related behaviors and confounding factors were also collected. The proposed study will test hypotheses, using prospective data on approximately 2,500 urban low income pregnant women, about depressive symptoms during pregnancy and preterm birth. Multivariable models will be used to allow for the control of potentially confounding factors. The findings will have important implications for research and intervention on preterm birth.